So if some TTRPGs do not contain an unwritten rule zero, and folk are saying that they can do whatever they could do with a written rule zero without a written rule zero (the analogy was given of Dumbo letting that feather go), can you say something more about that? On surface, it contains contradictions.
(1) "
All TTRPGs contain an unwritten Rule 0" and "
People can/will hack TTRPGs regardless of whether there is a Rule 0 or not" are not the same or equivalent positions. You are looking at the effects - i.e., participants can change the rules - and declaring that ergo all TTRPGs contain an unwritten Rule Zero. IMHO, this is an erroneous conclusion.
(2) Dumbo thinks he needs a magic feather to fly; however, Dumbo doesn't need a magic feather to fly. In fact, the feather isn't magical at all. I compared Rule 0 to Dumbo's magic feather. You have effectively declared in your first proposition the thesis that all TTRPGs have invisible magic feathers. TTRPGs can be hacked without a magic feather called Rule 0. Then saying that, therefore, "all TTRPGs have a written or unwritten Rule 0 at play" here ignores the fact that Rule 0 is entirely unnecessary for that process. We can safely ignore Rule 0 in the same way that Dumbo can ignore the feather. We don't need to talk about Rule 0's at all. It's redundant, meaningless, and pointless as a rule for the ends of changing the rules.
(3) And this gets to the next point: there are so many accumulated, nebulous ideas surrounding about what 'Rule 0' entails - including things such as "the GM is God Almighty" - that I find that the continued acknowledgement of 'Rule 0' does more harm than good as a concept. When we say that "all TTRPGs contain an unwritten Rule 0," then we risk bringing in those ideas to games that don't share the same idea about what play entails, the GM/players' role, the relationship of participants to the rules, etc.
I'm not sure what you mean by "implies real credence" and "that's not really the case". It's certainly possible to form a Rule Zero and give it normative effect. Do you mean "speaking subjectively, it lacks credence"? Perhaps expanding with "and here are my motives for saying that". As you go on to say -
Saying that "all TTRPGs contain an unwritten Rule 0" implies that these other games have a Rule 0 of some form or another. This argument gives credence to both the validity of Rule 0 as a rules concept and the presence of Rule 0 as a rule (written or otherwise) in other games. IMHO, that idea is untenable garbage.
I don't think that Rule 0 is necessary. I don't even think that Rule 0 is a good idea. It is
not because I believe that all TTRPGs have an unwritten Rule 0. It's because I believe that game hobbyists are gonna be game hobbyists, and game hobbyists are gonna hack, modify, and house rule games however they darn well please regardless of anything anyone says or does otherwise. TTRPGs don't need a Rule 0, written or unwritten, anymore than any other form of game does. Therefore, trying to chalk that up by saying that there must be a Rule 0 for all games seems ridiculous to me.
I don't need or want cook books, for example, to have a Rule 0 with platitudes that blows smoke up my butt about being the Chef and master of my kitchen to know that I and others can change the ingredients or cooking methods described in the recipe. I can just do it. No Rule 0 required. It's not because its an invisible or unwritten rule of cooking. And nothing is gained IMHO by pretending that my cooking would be improved by pretending that such a Rule 0 existed anymore than pretending that Santa Claus or the Tooth Fairy exist.
Is your position then that you accept the contention that there is a principle in play in all TTRPGs that is somewhat like rule zero, and you are able to (and hopefully will) articulate the cultural assumptions you fear it could smuggle in (so as to separate those out and address thought toward them)? For avoidance of doubt, those cultural assumptions amount to unwritten principles held by adherents of those "prevailing schools of thought in D&D play cultures" that they include in their play. Right? Implying that they are in addition to rule zero, and not part of rule zero?
I think that the framing of Rule 0 puts a lot of this discussion in terms of D&D and its prevailing norms, particularly in regards to GMs, which may or may not be shared in the wider hobby.
Even within the gaming culture of D&D and its ilk, there are a fairly wide variety of differing opinions throughout the games' history about what what is sometimes retroactively (if not inaccurately) called 'Rule 0.' There is a blog somewhere that walks through the history of "Rule 0," if one could even say such a thing, in D&D. It does vary fairly considerably. As I cited earlier, how 3e D&D first used and understood the term 'Rule 0' differs from how a variety of people in this thread understand its meaning and scope.